Besides dialysis, blood purification therapy known as apheresis has become popular as a treatment in which a liquid to be processed such as blood is removed from the body, and a pathogenic substance or the like in the liquid to be processed is returning the liquid into the body. Known examples of the apheresis therapy include simple plasma exchange; double filtration plasmapheresis; plasma adsorption, in which plasma is separated from blood, and a toxic substance in the plasma is removed; and direct hemoperfusion, in which a toxic substance is directly removed from whole blood.
In plasma adsorption, adsorption columns for adsorptive removal of autoantibodies, and adsorption columns for adsorptive removal of low-density lipoproteins have been practically used. In direct hemoperfusion, adsorption columns for adsorptive removal of endotoxins, and adsorption columns for adsorptive removal of β2-microglobulin (hereinafter referred to as β2-MG) have been practically used. They are all adsorptive carriers to which a ligand that interacts with the substance to be removed is immobilized.
As a material for adsorption of inflammatory cytokines, a protein-adsorbing carrier in which a ligand having an amino group is immobilized on the surface of a water-insoluble carrier composed of polystyrene or polysulfone has been disclosed (JP 2006-272075 A). A protein-adsorbing carrier in which a ligand having an amino group is immobilized on the surface of a water-insoluble carrier composed of a polyolefin such as polyethylene or polypropylene; a polyester such as polyethylene terephthalate or polybutylene terephthalate; a polysulfone-based polymer such as poly(p-phenylene ether sulfone); a polyetherimide-, polyimide-, polyamide-, polyether-, polyphenylene sulfide-, polystyrene (hereinafter referred to as “PS”)-, or polyacrylonitrile-based polymer; or a derivative of any of these macromolecular compounds, or a blended or alloyed product of any of these macromolecular compounds has also been disclosed (JP 2012-5827 A).
A protein-adsorbing carrier prepared by immobilizing a desired functional group on a polymer using an aldehyde or ketone having the functional group has also been disclosed (WO 2013/022012). WO 2013/022012 discloses, as the polymer, those containing an aromatic ring such as polystyrene, polysulfone, polyethersulfone, or polycarbonate.
The disclosed protein-adsorbing carriers are given high adsorption capacities by immobilization of a ligand.
However, in certain kinds of protein-adsorbing carriers, there is a possibility that the physical strength of the carrier decreases due to the process of immobilization of the ligand, causing generation and isolation of particulates from part of the carrier.
In view of this, it could be helpful to provide a fiber for protein adsorption and a column for protein adsorption having high capacity to adsorb a substance to be adsorbed, which are less likely to cause generation of particulates.